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EP1553113B1 - Biocompatible polymer and filter for selectively eliminating leucocytes using the same - Google Patents

Biocompatible polymer and filter for selectively eliminating leucocytes using the same Download PDF

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Publication number
EP1553113B1
EP1553113B1 EP03760160A EP03760160A EP1553113B1 EP 1553113 B1 EP1553113 B1 EP 1553113B1 EP 03760160 A EP03760160 A EP 03760160A EP 03760160 A EP03760160 A EP 03760160A EP 1553113 B1 EP1553113 B1 EP 1553113B1
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EP
European Patent Office
Prior art keywords
blood
leukocyte removal
polymer
selective leukocyte
filter material
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EP03760160A
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German (de)
English (en)
French (fr)
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EP1553113A4 (en
EP1553113A1 (en
Inventor
Susumu Kuno
Hirokazu Onodera
Masami Sakurai
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Asahi Kasei Medical Co Ltd
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Asahi Kasei Kuraray Medical Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A61M1/3627—Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
    • A61M1/3633—Blood component filters, e.g. leukocyte filters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/02—Blood transfusion apparatus
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
    • A61P1/04—Drugs for disorders of the alimentary tract or the digestive system for ulcers, gastritis or reflux esophagitis, e.g. antacids, inhibitors of acid secretion, mucosal protectants
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
    • A61P1/16—Drugs for disorders of the alimentary tract or the digestive system for liver or gallbladder disorders, e.g. hepatoprotective agents, cholagogues, litholytics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P13/00—Drugs for disorders of the urinary system
    • A61P13/12—Drugs for disorders of the urinary system of the kidneys
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P37/00—Drugs for immunological or allergic disorders
    • A61P37/02—Immunomodulators
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P37/00—Drugs for immunological or allergic disorders
    • A61P37/08—Antiallergic agents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P7/00—Drugs for disorders of the blood or the extracellular fluid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C08F220/1804—C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
    • C08F220/282—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing two or more oxygen atoms

Definitions

  • the present invention relates to a filter for selectively removing leukocytes which exhibits only slight adherence with platelets and can selectively remove leukocytes from blood. More particularly, the present invention relates to a filter material for selectively removing leukocytes in blood during transfusion or extracorporeal circulation, an apparatus for selectively removing leukocytes, and a system for selectively removing leukocytes.
  • a filter material for selectively removing leukocytes in blood during transfusion or extracorporeal circulation, an apparatus for selectively removing leukocytes, and a system for selectively removing leukocytes.
  • a polymer having excellent biocompatibility is present on the filter supporting body.
  • Blood component transfusion is an outstanding transfusion treatment exhibiting a high curative effect, while mitigating the load on patients during transfusion.
  • Various blood preparations used for the blood component transfusion such as concentrated erythrocytes, concentrated platelets, and platelet poor plasma, are prepared by centrifuging whole blood obtained by donation.
  • side reactions are induced after transfusion due to the leukocytes contained in these blood preparations because the blood preparations obtained by centrifugation contain many leukocytes.
  • the side reactions after transfusion include comparatively slight side reactions, such as headache, nausea, a chill, and a non-hemolytic exothermic reaction, as well as serious side reactions such as induction of graft versus host (GVH) reaction to a patient with an immune disorder in which the transfused leukocytes has a death-inducing effect on the skin and internal organs of the recipient, infection by viruses present in leukocytes such as cytomegalovirus infection, and alloantigen sensibilization. Removing leukocytes from the blood preparations is effective in preventing such side reactions after transfusion.
  • side reactions such as headache, nausea, a chill, and a non-hemolytic exothermic reaction
  • serious side reactions such as induction of graft versus host (GVH) reaction to a patient with an immune disorder in which the transfused leukocytes has a death-inducing effect on the skin and internal organs of the recipient, infection by viruses present in leukocytes such as cytomegalovirus infection, and allo
  • Methods for removing leukocytes from blood are broadly classified into a centrifuge separation method, making use of differences in the specific gravity of blood components, and a filter method using a fibrous medium such as non-woven fabric or a porous sponge-like material having three-dimensional continuous pore networks as a filter.
  • the filter method is more popular due to higher leukocyte removal efficiency, simple procedure, and lower cost.
  • Polymer materials consisting these leukocyte-removal filters are generally hydrophobic and cause other useful blood components such as platelets to adhere when removing leukocytes. It has been difficult to achieve a balance between the leukocyte-removal efficiency and the platelet recovery efficiency. Development of a material that can selectively remove leukocytes, while allowing platelets to pass through, has been strongly desired, particularly for patients with a disease, in which a decrease in platelets is undesirable, such as idiopathic thrombocytopenic purpura or autoimmune hepatitis.
  • JP-A 2000-245833 discloses a filter material for selectively removing leukocytes.
  • the material allows erythrocytes and platelets to pass through, but does not allow leukocytes to pass through.
  • the above problems have been overcome by coating a hydrophilic polymer onto the material forming the filter.
  • One possible problem with the coated filter material is elution of the hydrophilic polymer from the surface. Although the possibility of the polymer elution into an aqueous solution is very low, a material with a smaller risk of elution has been desired for use in processing of a large amount of blood, such as that used for extracorporeal circulation, to ensure stability of the filter material when it is kept in contact with an aqueous solution such as blood for a long time.
  • JP-A 07-25776 discloses a filter material coated with a polymer having both hydrophobic groups and hydrophilic polyethylene oxide chains. This is a filter material with a reduced risk of polymer elution by decreasing the solubility of the polymer in an aqueous solution by introducing hydrophobic groups into the polymer.
  • the polymer since the polymer has both hydrophobic groups and hydrophilic groups having opposite properties each other in the polymer molecule, the action of hydrophobic portions through which the polymer is caused to adhere to the filter supporting body which consists the filter material is reduced. It has, therefore, been difficult to ensure a balance between filter performance and elution properties using this technology alone.
  • the inventors of the present invention examined this technology using a polymer made from methyl methacrylate and methoxypoly(ethylene glycol methacrylate) having polyethylene oxide chains. As a result, the present inventors have found that aqueous solutions become turbid due to polymer elution.
  • a specific removing material surface can absorb viruses, remove leukocytes, and recover platelets and filed a patent application on the invention covering this finding ( PCT/JP 02/10766 , WO-A-03/033035 ).
  • this prior patent application describes the same polymer as the polymer of the present invention as an example of the polymer for forming a specific surface, the prior invention differs from the present invention in that the claimed filter removes viruses simultaneously with leukocytes.
  • the inventors of the present invention coated a specific supporting body with the polymer described in the prior application as one embodiment, of which the conditions of polymerization and purification differ from those applied to the present invention, and evaluated elution of the polymer.
  • the present inventors have found that a slight degree of elution occurred, although the degree was not so remarkable as to cause the test solution to become turbid. It is needless to mention that it is more desirable to further suppress the elution taking into consideration the application of the filter in a medical treatment.
  • Object of the present invention are to provide a filter material for selective removal of leukocytes, a filter apparatus for selective removal of leukocytes, and a system for selective removal of leukocytes using a polymer having an extremely low elution property and excellent biocompatibility, useful as a filter for selective removal of leukocytes which can selectively remove leukocytes from various bloods, particularly from whole blood, while preventing adsorption of platelets as much as possible.
  • the polymer that can be effectively used for platelet transfusion or extracorporeal circulation for leukocyte removal excels in biocompatibility, exhibits only a low adsorption to platelets, and has a low elution property.
  • a polymer comprising a unit originating from a polymerizable monomer having a polyalkylene oxide chain, a unit originating from a polymerizable monomer having a hydrophobic group, and a unit originating from a polymerizable monomer having a hydroxyl group at a specific ratio surprisingly exhibits remarkably low elution property, excellent biocompatibility, particularly low adsorption to platelets, and excellent selective leukocyte removal capability. This finding has led to the completion of the present invention.
  • the present invention provides a a selective leukocyte removal filter material wherein a biocompatible polymer comprising 8-45 mol% of a unit originating from a polymerizable monomer having a polyalkylene oxide chain, 30-90 mol% of a unit originating from a polymerizable monomer having a hydrophobic group, and 2-50 mol% of a unit originating from a polymerizable monomer having a hydroxyl group is present on at least the surface of a filter supporting body.
  • a biocompatible polymer comprising 8-45 mol% of a unit originating from a polymerizable monomer having a polyalkylene oxide chain, 30-90 mol% of a unit originating from a polymerizable monomer having a hydrophobic group, and 2-50 mol% of a unit originating from a polymerizable monomer having a hydroxyl group is present on at least the surface of a filter supporting body.
  • the present invention further relates to a selective leukocyte removal filter apparatus comprising the filter material of the invention packed in a container having at least a blood inlet port and a blood outlet port.
  • the present invention relates to a selective leukocyte removal system comprising the selective removal filter apparatus of the invention.
  • the polyalkylene oxide chain used in the present invention refers to a repeating structure in which an alkyl group and an oxygen atom bond alternately.
  • the polyalkylene oxide chains with an alkyl group having 2-4 carbon atoms such as a polyethylene oxide chain, polypropylene oxide chain, and polybutylene oxide chain, are preferable.
  • the polyalkylene oxide chain in the polymer exhibits a high platelet adsorption preventing effect due to the outstanding compatibility with blood possessed by the polyalkylene oxide chain.
  • the repeating number of the alkylene oxide chain used in the present invention is preferably from 2 to 10. If the number of repetitions is less than 2, it is difficult to obtain a sufficient platelet adsorption preventing effect. If the number of repetitions is more than 10, the polymer becomes less adhesive to the filter supporting body, thereby increasing a tendency of the polymer eluting more easily.
  • the number of repetitions is preferably 2 to 6, and more preferably 2 to 4.
  • Examples of the polymerizable monomer having the polyalkylene oxide chain include, but are not limited to, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, ethoxydipropylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, ethoxytriethylene glycol (meth)acrylate, ethoxytripropylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxytetrapropylene glycol (meth)acrylate, ethoxytetraethylene glycol (meth)acrylate, ethoxytetrapropylene glycol (meth)acrylate, methoxydiethylene glycol vinyl ether, ethoxydiethylene glycol vinyl ether, methoxytriethylene glyco
  • (meth)acrylate having a polyethylene glycol chain such as methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, ethoxytriethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, and ethoxytetraethylene glycol (meth) acrylate are preferably used due to the high platelet adsorption preventing effect.
  • Methoxydiethylene glycol (meth)acrylate is most preferable from the viewpoint of easy availability, easy handling, easy polymerization, and the like.
  • the (meth)acrylate in the present invention refers to acrylate or methacrylate, or both.
  • the polymer used in the filter material of the present invention it is necessary for the polymer used in the filter material of the present invention to contain the unit originating from the polymerizable monomer having a polyalkylene oxide chain in an amount from 8 mol% to 45 mol%. If less than 8 mol%, the platelet adsorption preventing effect of the polyalkylene oxide chain is insufficient, resulting in reduced platelet recovery performance. If more than 45 mol%, the hydrophobicity of the polymer decreases, giving rise to easy elution of the polymer when coming into contact with an aqueous solution such as blood.
  • the amount of the unit is preferably from 20 mol% to 40 mol%, and more preferably from 25 mol% to 35 mol%
  • unit in the present invention refers to a minimum recurring unit in a polymer molecule originating from respective polymerizable monomers.
  • polymerizable monomer having a hydrophobic group refers to a polymerizable monomer having solubility in water at 20°C of 0 wt% or more and less than 50 wt%, and not containing a polyalkylene oxide chain and a hydroxyl group in the molecule.
  • the unit originating from a polymerizable monomer having a hydrophobic group has effects of decreasing the solubility of the polymer in an aqueous solution, preventing elution of the polymer, and increasing leukocyte removal performance.
  • the solubility can be determined by a known method such as a dew point method, thermal analysis, electric method comprising measurement of the electromotive force or electric conductivity of the solution, gas chromatography analysis, and tracer method in the case where the monomer is a solid.
  • the solubility can be determined by, in addition to the methods applied to a solid monomer, a capacitance method, light scattering method, vapor pressure method, or the like, all of which are known in the art.
  • a simpler method when the monomer has a boiling point sufficiently higher than the boiling point of water, a method of vaporizing water from a saturated solution of the monomer and measuring the weight of the residue can be used.
  • polymerizable monomer having a hydrophobic group examples include styrene, methylstyrene, butyl (meth)acrylate, isobutyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, phenyl (meth) acrylate, ethylhexyl (meth) acrylate, and vinyl acetate can be given.
  • alkyl (meth)acrylates such as butyl (meth)acrylate, isobutyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate are preferably used due to their adequately hydrophobic and easily polymerizable properties.
  • Methyl (meth)acrylate is most preferable from the viewpoint of high biological safety.
  • the polymer of the present invention it is necessary for the polymer of the present invention to contain the unit originating from the polymerizable monomer having a hydrophobic group in an amount from 30 mol% to 90 mol%. If less than 30 mol%, the hydrophobicity of the polymer decreases, giving rise to easy elution of the polymer when coming into contact with an aqueous solution such as blood. If more than 90 mol%, the hydrophobicity of the polymer increases, giving rise to increased adsorption of platelets to the surface of the filter material.
  • the amount of the unit is preferably from 35 mol% to 80 mol%, and more preferably from 40 mol% to 70 mol%.
  • polymerizable monomer containing a hydroxyl group refers to a polymerizable monomer having a hydroxyl group, but not containing a polyalkylene oxide chain in the molecule.
  • polymerizable monomers containing an alkyl hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxyisobutyl (meth)acrylate, 3-hydroxyisobutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate are preferably used.
  • the polymer of the present invention it is necessary for the polymer of the present invention to contain the unit originating from the polymerizable monomer having a hydroxyl group in an amount from 2 mol% to 50 mol%. If less than 2 mol%, the hydrophilicity of the polymer decreases, giving rise to increased adsorption of platelets to the surface of the filter material. If more than 50 mol%, the hydrophobicity of the polymer decreases, giving rise to easy elution of the polymer when coming into contact with an aqueous solution such as blood.
  • the amount of the unit is preferably from 5 mol% to 40 mol%, and more preferably from 10 mol% to 30 mol%.
  • the content ratio of the unit originating from the polymerizable monomer having a hydroxyl group to the unit originating from the polymerizable monomer having a hydrophobic group in the polymer of the present invention is preferably from 0.05 to 1.
  • the content ratio in the present invention is a value obtained by dividing the mol content of the unit originating from the polymerizable monomer having a hydroxyl group by the mol content of the unit originating from the polymerizable monomer having a hydrophobic group in the polymer. If the content ratio is less than 0.05, the hydrophilicity provided by hydroxyl groups is canceled by hydrophobic groups and the hydrophilicity of the polymer decreases, giving rise to increased adsorption of platelets to the surface of the filter material.
  • the content ratio is preferably from 0.1 to 0.9, and more preferably from 0.15 to 0.8.
  • the polymerizable monomer having a hydroxyl group used in the polymer of the present invention preferably has solubility in water at 20°C in the range from 3 wt% or more,but less than 50 wt%. Due to the moderate hydrophilic and hydrophobic properties, the polymerizable monomer having a hydroxyl group provides the polymer with the effect of preventing adsorption of platelets and hydrophobic proteins together with the polyalkylene oxide chain, and, at the same time, the effect of preventing elution of the polymer together with a unit originating from strong hydrophobic polymerizable monomers.
  • 2-hydroxypropyl (meth)acrylate and 2-hydroxyisobutyl (meth)acrylate are preferably used due to their moderate hydrophilic and hydrophobic properties.
  • 2-hydroxyisobutyl (meth)acrylate is most preferable from the viewpoint of the moderate hydrophilic properties.
  • the chemical composition of a polymer can be determined by extracting the polymer using an appropriate solvent which does not dissolve the supporting body of the filter and analyzing the extract by a known method such as NMR spectrum, IR spectrum, and elemental analysis.
  • a known method such as NMR spectrum, IR spectrum, and elemental analysis.
  • known surface analytical methods such as X-ray photoelectron spectroscopy (ESCA) and a method of using an electron probe X-ray microanalyser (EPMA) can be used.
  • ESA X-ray photoelectron spectroscopy
  • EPMA electron probe X-ray microanalyser
  • the polymer of the present invention preferably has a weight average molecular weight (Mw) in the range of 100,000 to 3,000,000. If the Mw is less than 100,000, the molecular weight of the polymer decreases when the polymer is sterilized, particularly by radiation, giving rise to an increase in the eluted amount. If the weight average molecular weight (Mw) is more than 3,000,000, solubility of the polymer in the solvent used for coating decreases. In addition, there may be the case where the polymer cannot be produced in a stable manner.
  • the Mw is more preferably from 150,000 to 2,000,000, and most preferably from 200,000 to 1,500,000. Although the Mw can be determined by various known methods, a value determined by gel permeation chromatography (hereinafter abbreviated to GPC) using polymethyl methacrylate as a standard was used in the present invention.
  • the polymer may be either a random copolymer or a block copolymer.
  • the random copolymer is, however, more preferable since the block copolymer may have a tendency of decreasing the solubility in a solvent when used for coating and may have a tendency of impairing coating uniformity due to micelle formation in the solution.
  • a linear polymer is more preferable since a branched polymer may have a tendency of decreasing the solubility in a solvent when used for coating and may have a tendency of impairing coating uniformity due to micelle formation in the solution.
  • the polymer of the present invention is preferably a nonionic-type polymer.
  • nonionic refers to the properties of the polymer neither anionized nor cationized by blood or body fluid around the neutral pH, and containing neither a negatively charged functional group such as a carboxylic acid group, sulfonic group, phosphate group, and phenol group nor a positively charged functional group such as a primary amino group, secondary amino group, tertiary amino group, quaternary ammonium group, pyridyl group, and imidazoyl group in the molecule.
  • the blood clotting factor XII is said to be activated and cause a chain reaction in the clotting system on a negatively charged material surface.
  • a positively charged material surface tends to adsorb blood cells such as erythrocytes, platelets, and leukocytes due to the electrostatic interaction with the negative charge on the cell surface.
  • JP-A 06-51060 discloses a technology for removing leukocytes more efficiently while preventing platelet adsorption by providing a slightly positively charged surface.
  • electrostatic interaction is not desirable, because high platelet recovery performance is necessary for processing a large amount of blood.
  • the polymer is nonionic, the clotting system is activated only slightly so that stable platelet recovery performance can be attained even if the polymer is used for large scale blood treatment such as extracorporeal circulation.
  • a common polymerization method can be employed for synthesizing the polymer of the present invention.
  • Addition polymerization (vinyl polymerization) and the like involving chain reactions; isomerization polymerization; and dissociation reaction, polyaddition, polycondensation, addition polycondensation, and the like involving consecutive reactions may be employed. Radicals, ions, and the like can be used as chain carriers in producing the polymer.
  • solution polymerization As the type of polymerization, solution polymerization, mass polymerization, deposition polymerization, emulsion polymerization, and the like can be given. Of these, solution polymerization is preferable.
  • An example of the polymerization method is given below. An ethanol solution in which each monomer or a diazo initiator is dissolved is added dropwise to ethanol used as a polymerization solvent while stirring at a constant temperature below the boiling point of ethanol in a nitrogen atmosphere. A stabilizer and the like may be added as appropriate. The reaction yield is measured and confirmed by using a known method such as gas chromatography.
  • the reaction product may be purified by a common chemical purification method to remove impurities such as low molecular weight components and unreacted materials which are contained in the polymer or the reaction solution containing the polymer.
  • a purification method a method comprising dissolving the reaction mixture in a solvent that dissolves the impurities, but does not dissolve the polymer, to cause the polymer to precipitate, and separating the precipitate (polymer) by filtration, decantation, or the like can be given.
  • the precipitate is washed with a solvent with solubility slightly higher than that of the precipitation solvent (a mixture of the precipitation solvent and a solvent, for example) and the precipitate is dried under reduced pressure until the weight of the precipitate becomes constant, thereby obtaining a solid polymer.
  • a solvent with solubility slightly higher than that of the precipitation solvent a mixture of the precipitation solvent and a solvent, for example
  • the polymer can increase the biocompatibility of a medical material when coated on the surface.
  • the polymer can be used for artificial organs such as an artificial blood vessel, artificial kidney, and artificial liver, blood cell separation filters such as a leukocyte removal filter, dialysis membrane, anti-thrombus material, and the like.
  • the polymer can selectively remove leukocytes from blood, that is, a concentrated erythrocyte preparation, concentrated platelet preparation, platelet poor plasma preparation, peripheral blood, cell floating solutions containing leukocytes and platelets such as lymph and marrow fluid
  • the polymer can be suitably used as a selective leukocyte removal filter of blood preparations and a selective leukocyte removing filter for extracorporeal circulation.
  • the polymer since the polymer is eluted only with difficulty and is stable even if caused to be in contact with an aqueous solution for a long period of time, the polymer can be most suitably used for selective leukocyte removal apparatus for extracorporeal circulation designed to process a large amount of blood.
  • the present invention provides a filter material for selective removal of leukocytes characterized by having the biocompatible polymer of the present invention present at least on the surface of the filter supporting body.
  • the term "having the polymer present at least on the surface of the supporting material” indicates the polymer is present on the surface of the supporting material substantially covering the surface.
  • known methods such as a method of coating or depositing and insolubilizing the polymer on the supporting body of the filter, a method of phase-separating the polymer from the supporting body of the filter during fabrication, and the like can be used. Of these, the method of coating is most preferable due to the easy industrial applicability and excellent performance stability.
  • the polymer used for the filter material for selectively removing leukocytes of the present invention comes into contact with body fluids such as blood, it is desirable that the polymer has extremely low solubility in water.
  • the polymer has high adsorption with filter supporting material.
  • the index for solubility of the polymer in water and adsorption of the polymer with the filter supporting body the ⁇ -value of the solubility parameter described in J. H. Hildebrand and R. L. Scott, The Solubility of Nonelectrolytes, 3rd ed. (Dover Pub. , New York) can be used.
  • the polymer used for the filter material for selectively removing leukocytes of the present invention should preferably have a ⁇ -value that differs largely from the ⁇ -value (23.3) of water and is close to the ⁇ -value of the filter supporting body.
  • a combination of the polymer having a ⁇ -value in the range from 10.0 to 11.5 and the filter supporting body having the ⁇ -value of in the range from 7.0 to 15.0 can produce a filter material with extremely low solubility in water without a risk of detachment of the polymer from the filter supporting body.
  • a more preferable combination is the polymer's ⁇ -value of 10.0 to 10.8 and the filter supporting body's ⁇ -value of 7.2 to 14.5, and a still more preferable combination is the polymer's ⁇ -value of 10.0 to 10.5 and the filter supporting body's ⁇ -value of 7.5 to 14.0.
  • ⁇ E / V 1 / 2 wherein E is cohesive energy (cal mol -1 ) and V is molar volume (cm 3 mol -1 ).
  • the Adhesion Handbook Second Edition, edited by The Adhesion Society of Japan (THE NIKKAN KOGYO SHIMBUN, LTD. ) describes ⁇ -values of solvents and polymers measured heretofore. These values can be used. When the values E and V in the formula (1) are unknown, the ⁇ -values can be calculated from the molecular structure according to the Fedors method described in Kozo Shinoda, Solution and Solubility, Maruzen Co., Ltd.
  • the e (cohesive energy (cal mol -1 )) values and the v (molar volume (cm 3 mol -1 )) values that have been calculated by the Fedors for various structural units of compounds are integrated to determine the E value and V value of the compound.
  • the ⁇ -value of the compound is then calculated using the E value and V value. The resulting ⁇ -value is very close to the measured value.
  • any material having a ⁇ -value of the above range and not damaging blood cells can be used as the filter supporting body for the filter material for selectively removing leukocytes of the present invention without specific limitations.
  • polyester and polyolefin are preferable, with a particularly preferable organic filter material being polyester.
  • Various methods can be used for coating the polymer onto the filter supporting body without any specific limitations inasmuch as the surface of the filter supporting body can be coated with a certain degree of uniformity without unduly clogging the pores in the filter supporting body.
  • Examples of the method for coating the polymer onto the filter supporting body include, but are not limited to, a method of impregnating the filter supporting body with a polymer solution, a method of spraying the polymer solution to the filter supporting body, and a method of applying or transcribing the polymer solution to the filter supporting body using a rotogravure roll or the like.
  • the method of impregnating the filter supporting body with a polymer solution and the method of applying or transcribing the polymer solution to the filter supporting body using a rotogravure roll are preferable due to the excellent continuous productivity and low cost.
  • solvents that do not dissolve the filter supporting body to a noticeable degree can be used as the solvent to dissolve the polymer in the coating operation without any specific limitations.
  • a solvent include, but are not limited to, water and aqueous solutions containing an inorganic salt, alcohols such as methanol, ethanol, propanol, and butanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, hydrocarbons such as benzene and cyclohexane, halogenated hydrocarbons such as chloroform and dichloromethane, sulfur-containing solvents such as dimethyl sulfoxide, amides such as dimethylformamide and dimethylacetamide, and mixtures of two or more of the above solvents to the extent possible.
  • the concentration of the polymer solution used for coating is preferably 0.001 wt% or more, but less than 10 wt%. If the concentration is less than 0.001 wt%, the amount of the polymer on the surface is too small for the filter material to exhibit sufficient biocompatibility such as properties of preventing platelet adsorption. If the concentration is 10 wt% or more, on the other hand, not only does the solution have too great a viscosity to be handled with ease, but also the surface properties of the medical material may be significantly affected. In addition, such a high concentration is too expensive to be efficiently used.
  • the polymer concentration is more preferably 0.005 wt% or more, but less than 7 wt%, and most preferably 0.01 wt% or more, but less than 5 wt%.
  • the amount of the polymer held on the filter supporting material is preferably 0.001 wt% or more, but less than 10 wt%. If less than 0.001 wt%, the amount of the polymer on the surface is too small for the filter material to exhibit sufficient biocompatibility such as properties of preventing platelet adsorption. If 10 wt% or more, the amount of the polymer is excessive, giving rise to easy elution of the polymer when the filter material comes into contact with an aqueous solution such as blood. A more preferable amount of the polymer is 0.005 wt% or more, but less than 7 wt%, with the amount of 0.01 wt% or more, but less than 5 wt% being most preferable.
  • a method comprising removing excess solvent by mechanical compression, by gravity, or by injecting gas such as air or nitrogen, and treating the coated material in dry air or under reduced pressure at atmospheric temperature or with heating can be employed.
  • Adsorption of the polymer to the filter supporting body may be further increased by a heat treatment after coating the polymer or by post processing of irradiating the coated surface with ⁇ -rays, electron beams, or the like.
  • the coating operation may be carried out either during manufacturing the filter supporting body or after manufacturing the filter supporting body.
  • the polymer coating rate in the entire surface of the leukocyte removal filter material of the present invention is preferably from 40% to 90%.
  • the coating rate in the present invention refers to the proportion of the area covered with the polymer in the entire surface area of the filter supporting body. If the coating rate is less than 40 wt%, the amount of the polymer on the surface is too small for the filter material to exhibit sufficient biocompatibility such as properties of rejecting platelet adsorption. If 90 wt% or more, the amount of the polymer is excessive, giving rise to easy elution of the polymer when the filter material comes into contact with an aqueous solution such as blood. A more preferable range of coating rate is from 45% to 85%, with a still more preferable range being from 50% to 80%.
  • the coating rate can be determined using an analyzer commonly used to analyze polarized surfaces such as an XPS (X-ray Photoelectron Spectroscopy) analyzer or a TOF-SIMS (Time Of Flight-Secondary Ion Mass Spectrometry) analyzer.
  • an analyzer commonly used to analyze polarized surfaces such as an XPS (X-ray Photoelectron Spectroscopy) analyzer or a TOF-SIMS (Time Of Flight-Secondary Ion Mass Spectrometry) analyzer.
  • XPS X-ray Photoelectron Spectroscopy
  • TOF-SIMS Time Of Flight-Secondary Ion Mass Spectrometry
  • the coating rate can be determined as follows.
  • C1s spectra of the filter material coated with the polymer, the filter supporting body, and the polymer are measured using an XPS analyzer.
  • the height ratio of the peak (286 eV) originating from the -C-O- component and the peak (289 eV) originating from the -C-O-O- component in the Cls spectrum is determined.
  • the height ratio herein refers to the value calculated by dividing the height of the peak originating from the -C-O- component by the height of the peak originating from the -C-O-O- component.
  • the height ratio of polyethylene terephthalate is 1. Because the above polymer contains the -C-O- component other than that originating from the -C-O-O- component, the height ratio increases in proportion to the content of the polymer.
  • the filter material for selectively removing leukocytes of the present invention to have a configuration with a large surface area.
  • fibrous structural materials in the form of a nonwoven fabric, fiber, cotton, yarn, bundle, screen, and fabric; polymer porous materials such as sponge; and other structural materials in the form of beads, gel, and the like can be given.
  • Fabric and nonwoven fabric are particularly preferable in view of adsorptivity of leukocytes and handling easiness as a separating medium.
  • Nonwoven fabric is most preferable due to the capability of providing many contact points with leukocytes.
  • the average fiber diameter which affects the cell adsorption capability, is important. If the fiber diameter is too large, the amount and rate of adsorption of leukocytes decrease; if too small, the amount of platelet adsorption increases.
  • the average fiber diameter of the filter material of the present invention is preferably from 0.5 ⁇ m to 50 ⁇ m, and more preferably from 1 ⁇ m to 40 ⁇ m, and most preferably from 2 ⁇ m to 35 ⁇ m.
  • the average fiber diameter in the present invention is determined as follows. A portion deemed to be substantially homogeneous is sampled from one or more pieces of fabrics forming the filter material and photographed using a scanning electron microscope or the like. For sampling, an effective filtration cross-sectional area of the fabric is divided into squares with one side length of 0.5 cm and six squares are randomly sampled. In random sampling, each divided square is numbered and the required number of squares is selected by using a table of random numbers, for example. Photographs with a magnification of 2,500 are taken at three or more, preferably five or more locations for each sampled square. Photographs for the central parts and the neighborhood areas of each sampled square are taken until the total number of fibers taken in the photographs becomes 100.
  • the diameter herein refers to the width of fiber in the direction perpendicular to the fiber axis. Then, the average diameter is determined by dividing the sum of the diameters of all measured fibers by the number of the fibers. However, the data obtained are excluded, for example, in the cases where multiple fibers overlap precluding diameter measurement of a fiber which hides itself behind another fiber, multiple fibers are consolidated into a fiber with a larger diameter due to fusing or else, or there are fibers with remarkably different diameters.
  • the present invention also provides a filter apparatus for selective removal of leukocytes characterized by having the filter material of the present invention filled in a container having at least an inlet port and an outlet port.
  • a container having at least an inlet port and an outlet port.
  • Examples of such a container include a container in which the filter material for selectively removing leukocytes can be filled in the form of laminated layers, a cylindrical container, a columnar container such as a triangular prism, a quadratic prism, a hexagonal cylinder, and octagonal cylinder, a container in which the filter material for selectively removing leukocytes rolled in the form of a cylinder can be filled, and a cylindrical container allowing a blood flow to come into the cylinder from the outer perimeter, converging blood into the innermost area, and letting the blood to flow out from an outlet port. Furthermore, a container in which the cross-sectional area decreases from the inlet port toward the outlet port is preferably used.
  • the filling density of the filter material for selectively removing leukocytes in the container of the present invention is from 0.05 g/cm 3 to 0.5 g/cm 3 .
  • the filling density is preferably from 0.075 g/cm 3 to 0.4 g/cm 3 , and most preferably from 0.1 g/cm 3 to 0.35 g/cm 3 .
  • Figure 1 is a cross-sectional view of one embodiment of the filter apparatus for selectively removing leukocytes of the present invention.
  • the filter material for selectively removing leukocytes is rolled in the form of a cylinder to provide a hollow cylindrical filter (4), which is packed in a cylindrical container (2) with the both ends (5, 5) being sealed liquid-tight so as not to allow blood to flow.
  • a sealing material with excellent compatibility with blood when caused to come in contact with blood and possessing liquid-tight properties is used.
  • Known synthetic resins such as urethane can be used.
  • a blood inlet port (3) may be provided at any optional location of the container which allows the blood to be processed to be supplied to the outer or inner perimeter of the hollow cylindrical filter of which the both ends are sealed.
  • a blood outlet port (6) may be provided in any location communicated with the inner perimeter when the blood to be processed is supplied to the outer perimeter or any location communicated with the outer perimeter when the blood to be processed is supplied to the inner perimeter.
  • the hollow cylindrical filter in the filter apparatus for selective removal of leukocytes of the present invention preferably has a filtration area of the first blood contact layer (4a) from 50 cm 2 to 1,000 cm 2 .
  • the first blood contact layer in the present invention refers to a part of the hollow cylindrical filter with which the blood to be processed supplied from the inlet port comes into contact for the first time.
  • the first blood contact layer may be any part of the outer or inner perimeter of the hollow cylindrical filter. Platelets are said to abundantly bond with the von Willebrand factor through GPIIb/IIIa acceptor under a high shearing stress and to undergo activated clotting. Therefore, to increase the platelet recovery rate, it is desirable to cause the blood to come into contact with the first contact layer moderately at a low flow rate.
  • the filtration area of the first blood contact layer is less than 50 cm 2 , the blood flow rate per unit filtration area increases, resulting in a reduction in the platelet recovery rate. If the filtration area of the first blood contact layer is more than 1,000 cm 2 , a large container is required for the filter apparatus.
  • the filtration area is more preferably from 80 cm 2 to 500 cm 2 , and still more preferably from 100 cm 2 to 400 cm 2 .
  • the volume standard specific surface area of the first blood contact layer in an appropriate range is preferable from the viewpoint of preventing the shearing stress given to platelets.
  • the volume standard specific surface area as used in the present invention refers to the surface area per unit volume of the filter material and can be measured by a known method such as the BET method or the Langmuir method.
  • the volume standard specific surface area can be calculated using the average fiber diameter, the specific gravity of fiber, and the like.
  • the hollow cylindrical filter in the filter apparatus for removing leukocytes of the present invention preferably has a volume standard specific surface area of the first blood contact layer in a range from 0.08 m 2 /ml to 1.0 m 2 /ml.
  • the volume standard specific surface area is more preferably from 0.1 m 2 /ml to 0.8 m 2 /ml, and still more from 0.2 m 2 /ml to 0.5 m 2 /ml.
  • the hollow cylindrical filter in the filter apparatus for removing leukocytes of the present invention may be a scroll of a laminated body made of a filter material and a spacer layer material both in the form of a sheet.
  • the term "spacer layer" in the present invention refers to a layer of a material in which blood can flow more easily than in the filter material for selectively removing leukocytes.
  • a coarse mesh of metal, synthetic resin, inorganic fiber, or synthetic fiber, nonwoven fabric with an average fiber diameter larger than the nonwoven fabric used for the hollow cylindrical filter, and the like can be used as the spacer layer material.
  • the spacer layer is laminated with the filter material for selectively removing leukocytes and rolled in the form of a scroll of cloth to secure the area that permits blood to easily flow between the hollow cylindrical filter.
  • Both the starting and terminal ends of the spacer layer rolled in the form of a scroll are preferably open to the outer perimeter and/or the inner perimeter of the hollow cylindrical filter to provide a passage for blood.
  • the thickness of the hollow cylindrical filter in the leukocyte removal filter apparatus of the present invention is preferably from 0.6 mm to 12.0 mm. If the thickness is less than 0.6 mm, the filtration length is too small to provide blood components with sufficient opportunity to contact with the filter material, resulting in a poor leukocyte removal efficiency. If the thickness is more than 12.0 mm, the filtration length is so large that blood components are provided with too many opportunities to contact with the filter material, resulting in a decrease in the platelet recovery rate.
  • a more preferable thickness range of the hollow cylindrical filter is from 1.0 mm to 10.0 mm, with a still more preferable thickness range being from 1.5 mm to 8.0 mm.
  • the hollow cylindrical filter in the filter apparatus for removing leukocytes of the present invention may be provided with a second blood contact layer on the downstream side of the first blood contact layer. Since the second blood contact layer has a function of removing leukocytes which have not been removed in the first blood contact layer, the second blood contact layer must have a volume standard specific surface area larger than that of the first blood contact layer.
  • a preferable range of the volume standard specific surface area of the second blood contact layer is from 1.0 m 2 /ml to 20 m 2 /ml, and still more from 2.0 m 2 /ml to 15 m 2 /ml.
  • the thickness ratio of the laminated layers is preferably from 0.2 to 10.0.
  • the thickness ratio of the laminated layers in the present invention refers to the value obtained by dividing the thickness of the first blood contact layer by the thickness of the second blood contact layer. If the thickness ratio of the laminated layers is less than 0.2, the filtration length of the first blood contact layer is comparatively small. Therefore, the first blood contact layer cannot sufficiently mitigate the shearing stress which platelets receive in the second blood contact layer, giving rise to a decrease in the platelet recovery rate.
  • the laminated layer thickness of more than 10.0 mm is undesirable because the volume of the first blood contact layer becomes large, so that a large container is required for the filter apparatus. For these reasons, the laminated layer thickness is more preferably from 0.3 to 8.0, and most preferably from 0.5 to 6.0.
  • the selective leukocyte removal filter apparatus of the present invention can be sterilized by a known method such as radiation sterilization, moist heat sterilization, chemical sterilization, gas sterilization, and dry heat sterilization.
  • Moist sterilization by maintaining the filter material under the condition of the saturated moisture content or more using a filling liquid is preferable due to the simple priming operation.
  • a more preferable method is radiation sterilization comprising irradiating the filter material with radiation such as ⁇ -ray and electron beams or moist heat sterilization using high pressure steam or the like.
  • any liquid not causing deterioration of the polymer can be used as the filling liquid, water or an aqueous solution of a water soluble substance having a minimal risk of damage to living bodies is preferable.
  • water-soluble substance having a minimal risk of damage to living bodies compounds soluble in water exhibiting only a slight damage to living bodies, for example, salts such as sodium chloride, sodium carbonate, sodium hydrogencarbonate, sodium phosphate, sodium hydrogenphosphate, and sodium pyrosulfite, and water-soluble organic compounds such as glycerol, sodium citrate, gelatin, and casein can be given.
  • salts such as sodium chloride, sodium carbonate, sodium hydrogencarbonate, sodium phosphate, sodium hydrogenphosphate, and sodium pyrosulfite
  • water-soluble organic compounds such as glycerol, sodium citrate, gelatin, and casein
  • a compound which may be harmful to living bodies if present in a large amount can also be used, if such a compound can be washed out from the blood cell separating filter by a simple washing procedure such as a priming operation to an extent that only a small amount not harmful to the living body remains after washing.
  • a compound which can easily form an isotonic solution when dissolved in water may be very preferably used. These compounds can be used either individually or in combination of two or more.
  • Preferable water-soluble compounds are sodium chloride, sodium carbonate, sodium hydrogencarbonate, sodium phosphate, sodium hydrogenphosphate, and sodium pyrosulfite, with sodium chloride being most preferable.
  • the condition of the saturated moisture content or more used herein may include a condition in which the filter material is entirely immersed in water of an aqueous solution of water soluble compound having a minimal risk to living bodies or a condition in which the filter material is sufficiently humidified in advance to become moistened to the saturated moisture content or more of the material. In short, it is sufficient for the filter material to be exposed to moisture in the amount equivalent to or more of the saturated moisture content of the filter material irrespective of the degree of exposure.
  • the concentration of the aqueous solution is preferably 5.0 wt% or less. If the concentration exceeds 5.0 wt%, it is difficult to remove the water-soluble substance by the priming operation. Since elution of the polymer can be prevented at a higher more certainty at a concentration of 0.01 wt% or more, a more preferable concentration range is from 0.01 wt% to 4.0 wt%, with a still more preferable concentration being from 0.1 wt% to 3.0 wt%.
  • the present invention also provides a system for selective removal of leukocytes comprising a blood delivery means, an anticoagulant fluid injection means, and a selective leukocyte removal means which contains the selective leukocyte removal filter apparatus of the present invention.
  • the system for selective removal of leukocytes of the present invention can maintain stable selective leukocyte removal capability while preventing platelet adsorption even if a large amount of blood (e.g. 1-10 1) is processed.
  • any known liquid delivery means such as a pump can be used as the blood delivery means.
  • a pump an inner-tube roller pump, a finger pump, and the like can be given.
  • the blood flow rate using the blood delivery means in the selective leukocyte removal system of the present invention is preferably from 10 ml/min to 200 ml/min. If the blood flow rate is less than 10 ml/min, the blood tends to stagnate in the selective leukocyte removal filter apparatus. If the flow rate is greater than 200 ml/min, the shearing stress significantly increases, resulting in a decrease of the platelet recovery rate. For these reasons, the blood flow rate is more preferably from 15 ml/min to 150 ml/min, and most preferably from 20 ml/min to 100 ml/min.
  • the anticoagulant fluid injection means used in the present invention preferably has a capacity of feeding the anticoagulant fluid to the blood flow circuit at a flow rate from 1% to 20% of the blood flow rate.
  • the anticoagulant may be charged either as is or after dilution. If the flow rate is less than 1% of the blood flow rate, it is difficult for the anticoagulant to mix with the blood and, therefore, to exhibit a sufficient anticoagulation effect.
  • the flow rate of the anticoagulant more than 20% of the blood flow rate is not desirable in practice, because the blood may be excessively diluted. For these reasons, the flow rate of the anticoagulant fluid is more preferably from 3% to 18%, and most preferably from 5% to 18% of the blood flow rate.
  • heparins such as heparin sodium, heparin calcium, and dalteparin sodium
  • protease inhibitors such as nafamostat mesilate and gabexate mesilate
  • citric acid-based anticoagulants such as ACD-A, ACD-B, and CPD; and the like
  • the above anticoagulants can be used more efficiently, when diluted with a buffer solution such as a physiological saline solution or a glucose solution which neither affects the anticoagulation effect nor denatures blood constituents.
  • the amount of the anticoagulant added to 1 1 of blood is from 100 to 2,000 units, and preferably from 300 to 1,500 units.
  • the amount is from 2 to 40 mg, and preferably from 6 to 30 mg.
  • the effective anticoagulant amount is from 20 to 160 ml, and preferably from 30 to 125 ml.
  • any means for adding an anticoagulant solution any means typified by commonly used metering pumps such as a roller inner tube pump, finger pump, infusion pump, and syringe pump can be used. More specifically, an inner tube roller pump, a finger pump, and the like by which a very small quantity of a fluid can be injected at a high precision can be suitably used.
  • the selective leukocyte removal system of the present invention can be constructed by liquid-tight joining of the above-described blood delivery means, anticoagulant fluid injection means, and selective leukocyte removal means using a blood circuit to introduce blood to the selective leukocyte removal means and a blood circuit to discharge the blood from the selective leukocyte removal means, thereby forming a circuit for extracorporeal circulation.
  • the blood delivery means and the anticoagulant fluid injection means are provided in the circuit on the blood introduction side having a blood recovering means, for example, and this circuit is joined to the blood inlet port side of the selective leukocyte removal means.
  • the system can be preferably used for extracorporeal circulation if the blood discharge side circuit having a means for returning blood to the patient is provided on the blood exit side of the selective leukocyte removal means.
  • FIG 2 is a schematic diagram showing one embodiment of the selective leukocyte removal system of the present invention.
  • the system comprises a means (7) to extract blood from a patient, an anticoagulant fluid injection means (8) to inject an anticoagulant fluid (8a) into the extracted blood, a blood delivery means (9) to deliver the blood mixed with the anticoagulant at a flow rate of 10-200 ml/min, a micro aggregate capture means (12) having an arterial pressure monitor (12a), and a selective leukocyte removal filter apparatus.
  • a selective leukocyte removal means (10) having an inlet port and a blood outlet port, a drip chamber (13) having a venous pressure monitor (13a), and a means (11) to return the blood to the patient are liquid tightly connected in that order.
  • the selective leukocyte removal filter material according to the invention can be used for treating cellular immune abnormality, comprising causing the blood of a patient suffering from the cellular immune abnormality to come in contact with the filter of the present invention. To complete the medical treatment of the disease the blood after processing may be returned to the patient. This can be preferably carried out by applying various means and methods of use described in connection with the selective leukocyte removal system.
  • the cellular immune abnormality as referred to herein is a disease in which immunocompetent cells, cytotoxic-T cells, inflammatory cells, and the like in the living body present abnormalities to produce an inflammation inducing substance such as cytokine, by which the body tissues are attacked.
  • Autoimmune diseases such as or malignant rheumatoid arthritis, systemic erythematodes, Behcet's disease, idiopathic thrombo cytopenic purpura, and autoimmune hepatitis; inflammatory bowel diseases such as ulcerative colitis and Crohn's disease; allergic diseases such as atopic dermatitis; rapidly progressive glomerulonephritis; and systemic inflammatory response syndrome are given as examples.
  • the selective leukocyte removal system of the present invention has leukocyte removal capability in terms of the leukocyte removal rate of 50% or more.
  • the leukocyte removal rate can be determined in the present invention from the leukocyte concentration in the blood on the inlet port side introduced into the selective leukocyte removal means and the leukocyte concentration in the blood on the outlet port side discharged from the selective leukocyte removal means according to the following formula.
  • Leukocyte removal rate % 1 - Leukocyte concentration on the outlet port side / Leukocyte concentration on the inlet port side ⁇ 100
  • leukocyte removal rate is less than 50%, the amount of leukocytes removed in one process is not sufficient, only giving a limited improvement effect on the cellular immune abnormality.
  • a more preferable leukocyte removal rate is 60% or more, with a 70% or more leukocyte removal rate being most preferable.
  • the platelet recovery rate is 50% or more.
  • the platelet recovery rate can be determined in the present invention from the platelet concentration in the blood on the inlet port side introduced into the selective leukocyte removal means and the platelet concentration in the blood on the outlet port side discharged from the selective leukocyte removal means according to the following formula.
  • Platelet recovery rate % Platelet concentration on the outlet port side / Platelet concentration on the inlet port side ⁇ 100
  • the platelet recovery rate is less than 50%, the amount of platelet recovered may be too small when processing blood containing a small amount of platelets (e.g. 100,000 platelets/ ⁇ l or less).
  • a more preferable platelet recovery rate is 60% or more, with a 70% or more platelet recovery rate being most preferable.
  • a reaction vessel equipped with a reflux condenser was charged with ethanol (277 ml). After bubbling nitrogen into ethanol and stirring the mixture at 73°C for one hour, monomers were added dropwise over 120 minutes while maintaining a nitrogen atmosphere. An initiator solution was added dropwise at the same time over 300 minutes. After completion of the addition of the initiator solution, the monomers were polymerized for further two hours.
  • the monomer mixture was a liquid containing 4.8 g (30.0 mmol) of methoxydiethylene glycol methacrylate (MDG), which is a polymerizable monomer having an alkylene oxide chain, 4.3 g (50.0 mmol) of methylmethacrylate (MMA), which is a polymerizable monomer having a hydrophobic group, and 2.7 g (20.0 mmol) of 2-hydroxyisobutyl methacrylate (HBMA), which is a polymerizable monomer having a hydroxyl group.
  • MDG methoxydiethylene glycol methacrylate
  • MMA methylmethacrylate
  • HBMA 2-hydroxyisobutyl methacrylate
  • the molar ratio of the monomers was 30 mol% (MDG) : 50 mol% (MMA) : 20 mol% (HBMA).
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.29.
  • the weight average molecular weight of the polymer measured by GPC was 6.8 x 10 5 .
  • the method of the elution test was as follows. A 200 ml container was packed with 15 g of the filter material prepared in the above, a physiological saline solution was filled into the container, and the content was sterilized with ⁇ -ray (irradiation dose: 25 kGy). To confirm elution in the temperature range possibly occurring during actual preservation of medical devices, the container was allowed to stand at 25°C for 24 hours, then at 4°C for 24 hours. The appearance of the filled solution after preservation was observed to confirm that the solution was transparent and colorless, with no change as compared with the state before sterilization. The maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer (V-560, manufactured by JASCO Corp.) at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.04.
  • V-560 ultraviolet spectrophotometer
  • the filter material prepared in the above was cut into disks, each with a diameter of 6.8 mm. Seven sheets of the disks were laminated in a 1 ml column having an inlet port and an outlet port. The column was filled with a physiological saline solution and sterilized with ⁇ -ray (irradiation dose: 25 kGy) to prepare the column for performance evaluation.
  • the leukocyte removal rate was 97.5% and the platelet recovery rate was 85.0%, confirming selective leukocyte removal capability.
  • a polymer was synthesized in the same manner as in Example 1, except for using 40.0 mol% of MDG, 50.0 mol% of MMA, and 10 mol% of HBMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.04.
  • the weight average molecular weight of the polymer measured by GPC was 8.7 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the appearance of the filled solution after sterilization and preservation confirmed that the solution was transparent and colorless, with no change as compared with the state before sterilization.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.05.
  • the leukocyte removal rate was 97.0% and the platelet recovery rate was 85.0%, confirming selective leukocyte removal capability.
  • a polymer was synthesized in the same manner as in Example 1, except for using 20 mol% of MDG, 60 mol% of MMA, and 20 mol% of HBMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.31.
  • the weight average molecular weight of the polymer measured by GPC was 9.2 x 10 5 .
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the appearance of the filled solution after sterilization and preservation confirmed that the solution was transparent and colorless, with no change as compared with the state before sterilization.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.08.
  • the leukocyte removal rate was 98.5% and the platelet recovery rate 89.4%, confirming selective leukocyte removal capability.
  • a polymer was synthesized in the same manner as in Example 1, except for using n-butyl methacrylate (BMA) as a polymerizable monomer having a hydrophobic group and 2-hydroxyisopropyl methacrylate (HPMA) as a polymerizable monomer having a hydroxyl group, and charging 20 mol% of MDG, 50 mol% of BMA, and 30 mol% of HPMA.
  • BMA n-butyl methacrylate
  • HPMA 2-hydroxyisopropyl methacrylate
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.46.
  • the weight average molecular weight of the polymer measured by GPC was 1.1 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the appearance of the filled solution after sterilization and preservation confirmed that the solution was transparent and colorless, with no change as compared with the state before sterilization.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.08.
  • the leukocyte removal rate was 93.8% and the platelet recovery rate was 83.7%, confirming selective leukocyte removal capability.
  • a polymer was synthesized in the same manner as in Example 1, except for using 15 mol% of MDG, 40 mol% of MMA, and 45 mol% of HBMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.86.
  • the weight average molecular weight of the polymer measured by GPC was 2.1 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the appearance of the filled solution after sterilization and preservation confirmed that the solution was transparent and colorless, with no change as compared with the state before sterilization.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.15.
  • the leukocyte removal rate was 82.2% and the platelet recovery rate was 80.2%, confirming selective leukocyte removal capability.
  • a polymer was synthesized in the same manner as in Example 1, except for using 5.0 mol% of MDG, 5.0 mol% of MMA, and 90.0 mol% of HPMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 12.39.
  • the weight average molecular weight of the polymer measured by GPC was 3.2 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the filled solution after sterilization and preservation was turbid, confirming that the polymer eluted during sterilization and preservation.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 2.4.
  • the leukocyte removal rate was 93.3% and the platelet recovery rate 3.1%, confirming a low platelet recovery rate.
  • a polymer was synthesized in the same manner as in Example 1, except for using methoxynonaethylene glycol methacrylate (MNG) as a polymerizable monomer having a polyalkylene oxide chain and charging 65.0 mol% of MNG and 35.0 mol% of MMA.
  • MNG methoxynonaethylene glycol methacrylate
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 9.64.
  • the weight average molecular weight of the polymer measured by GPC was 2.2 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the filled solution after sterilization and preservation was turbid, confirming that the polymer eluted during sterilization and preservation.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 5.0 or more.
  • the leukocyte removal rate was 99.5% and the platelet recovery rate was 52.0%.
  • a polymer was synthesized in the same manner as in Example 1, except for using 5.0 mol% of MDG, 50.0 mol% of MMA, and 45.0 mol% of HBMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.89.
  • the weight average molecular weight of the polymer measured by GPC was 1.2 x 10 5 .
  • the ⁇ value of the filter supporting body was 15. 65, the average fiber diameter of the filter material was 4.1 ⁇ m, the density was 18 g/m 2 , and the thickness was 0.1 mm.
  • Example 2 Using the prepared filter material, the elution test was carried out in the same manner as in Example 1. The filled solution after sterilization and preservation was turbid, confirming that the polymer eluted during sterilization and preservation. The maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 5.0 or more.
  • the filter material prepared in the above was cut into disks, each with a diameter of 6.8 mm. 28 sheets of the disks were laminated in a 1 ml column having an inlet port and an outlet port.
  • the blood performance test was carried out in the same manner as in Example 1.
  • the leukocyte removal rate was 85.1% and the platelet recovery rate 45.4%, confirming rather low recovery rate of platelets.
  • a polymer was synthesized in the same manner as in Example 1, except for using 90.0 mol% of MDG and 10.0 mol% of MMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 9.70.
  • the weight average molecular weight of the polymer measured by GPC was 3.5 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the filled solution after sterilization and preservation was turbid, confirming that the polymer eluted during sterilization and preservation.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 5.0 or more.
  • the leukocyte removal rate was 97.0% and the platelet recovery rate was 78.0%.
  • a polymer was synthesized in the same manner as in Example 1, except for using 40.0 mol% of MDG, 25.0 mol% of MMA, and 35.0 mol% of HBMA.
  • the composition of the resulting polymer was analyzed from the integral value of NMR measurement, confirming that the composition was almost in agreement with the charged monomer composition.
  • the ⁇ value of the polymer was calculated according to the Fedors method to confirm that the ⁇ value was 10.58.
  • the weight average molecular weight of the polymer measured by GPC was 4.2 x 10 5 .
  • a filter material was prepared from the polymer in the same manner as in Example 1.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.7 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.42 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the filled solution after sterilization and preservation was turbid, confirming that the polymer eluted during sterilization and preservation.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 2.3.
  • the leukocyte removal rate was 85.8% and the platelet recovery rate was 72.7%.
  • 1 g of the polymer thus obtained was dissolved in 99 g of a 70% aqueous solution of ethanol to obtain a 1% coating solution.
  • 1 g of a nonwoven fabric made from polyethylene terephthalate was immersed in 10 ml of the 1% coating solution and dried at 25°C for 12 hours to obtain a filter material.
  • the ⁇ value of the filter supporting body was 10.30, the average fiber diameter of the filter material was 2.9 ⁇ m, the density was 90 g/m 2 , and the thickness was 0.40 mm.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the appearance of the filled solution after sterilization and preservation was transparent and colorless.
  • the maximum absorbance of the filled solution measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm was 0.41, indicating elution of a small amount of the polymer.
  • the leukocyte removal rate was 95.1% and the platelet recovery rate was 74.3%.
  • Example Comparative Example 1 2 3 4 5 6 1 2 3 4 5 Polymerizable monomer having polyalkylene oxide chain (mol %) 30 40 20 20 15 30 5 65 5 90 40 Polymerizable monomer having a hydrophobic group (mol %) 50 50 60 50 40 50 5 35 50 10 25 Polymerizable monomer having hydroxyl group (mol %) 20 10 20 30 45 20 90 0 45 0 35 Weight average molecular weight of polymer 6.8x10 5 8.7x10 5 9.2x10 5 1.1x10 5 7.2x10 5 4.0x10 4 3.2x10 5 2.2x10 5 1.2x10 5 3.5x10 5 4.2x10 5 ⁇ -Value of polymer 10.29 10.04 10.31 10.46 10.86 10.29 12.39 9.64 10.89 9.70 10.58 ⁇ -Value of filter supporting body 10.30 10.30 7.90 10.30 10.30 10.30 10.30 10.30 15.65 10.30 10.30 Elution test: Filling solution appearance* Tp Tp Tp Tp Tp
  • the filter materials using a polymer comprising a unit originating from a polymerizable monomer having a polyalkylene oxide chain, a unit originating from a polymerizable monomer having a hydrophobic group, and a unit originating from a polymerizable monomer having a hydroxyl group at a specific ratio were confirmed to elute only a minimal amount of polymer components and to exhibit selective leukocyte removal capability.
  • the filter materials using a polymer not satisfying these conditions did not satisfy either the elution test or the blood performance test, or both.
  • the filter material using a polymer with a weight average molecular weight of 100,000 or more was found to achieve excellent results in the eluting test.
  • the filter material was prepared in the same manner as in Example 1, except that 10 g of the polymer was dissolved in 100 ml of a mixed solvent of ethanol and purified water (70:30) .
  • the polymer retained by the filter material was measured to find that the filter material contained was 20 wt% of the polymer as compared with 2 wt% in the filter material of Example 1.
  • the amount of the polymer retained by the filter material was calculated from the weight change of the filter material before and after coating.
  • Example 2 Using the obtained filter material, the elution test and the blood performance test were carried out in the same manner as in Example 1.
  • the maximum absorbance of the filled solution was measured using an ultraviolet spectrophotometer at a wavelength of 220 nm to 350 nm to find that the maximum absorbance was 0.21.
  • the leukocyte removal rate was 92.3% and the platelet recovery rate 82.1%, confirming the selective leukocyte removal capability.
  • Example 1 4.0 g of the polymer obtained in Example 1 was dissolved in 500 ml of a mixed solvent of ethanol and purified water (70:30) .
  • 0.5 g of the polymer obtained in Example 1 was dissolved in 500 ml of a mixed solvent of ethanol and purified water (70:30).
  • a nonwoven fabric made from polyethylene terephthalate with an average fiber diameter of 12 ⁇ m, a density of 30 g/m 2 , and a thickness of 0.20 mm was immersed in the solvent. After removing excessive liquid, the nonwoven fabric was dried at room temperature for 16 hours to obtain a filter material (B).
  • the filter material (A) was cut into a sheet (width: 150 mm, length: 250 mm) and the sheet was wound around a cylindrical polyethylene mesh with a diameter of 28 mm.
  • the filter material (B) cut into a rectangle of 150 mm x 1,660 mm was wound around the cylinder and laminated over the filter material (A).
  • a polyethylene mesh with a width of 150 mm and a length of 130 mm was further wound around the filter material (B) to obtain a hollow cylindrical filter.
  • the cylinder was placed in a cylindrical polycarbonate container with an internal diameter of 41 mm of which the top and the bottom were respectively provided with a blood inlet port and a blood outlet port, so that the outer circumference of the cylinder was connected to the blood inlet port of the container and the inner circumference of the cylinder was connected to the blood outlet port of the container.
  • the container was filled with a physiological saline solution and sterilized with ⁇ -ray (irradiation dose: 25 kGy) to prepare a selective leukocyte removal filter apparatus.
  • the filling density of the filter material was 0.157 g/cm 3
  • the filtration area of the first blood contact layer was 174 cm 2
  • the volume standard specific surface area of the first blood contact layer was 0.33 m 2 /ml
  • the volume standard specific surface area of the second blood contact layer was 1.5 m 2 /ml
  • the laminated layer thickness ratio of the first blood contact layer to the second blood contact layer was 4.0
  • the thickness of the hollow cylindrical filter was 4.5 mm.
  • a selective leukocyte removal system for treating blood of a patient of ulcerative colitis shown in Figure 2 was prepared. Extracorporeal circulation, each treatment being for one hour at a flow rate of 50 ml/min, was conducted five times for each patient at a frequency of once a week using the selective leukocyte removal system in which the above filter apparatus was used.
  • As an anticoagulant solution a mixture of 3,000 units of heparin and 500 ml of a physiological saline solution was continuously injected at a flow rate of 8 ml/min.
  • a selective leukocyte removal system for treating blood of a patient of rheumatism shown in Figure 2 was prepared. Extracorporeal circulation, each treatment being for one hour at a flow rate of 50 ml/min, was conducted seven times for each patient at a frequency of once a week using the selective leukocyte removal system in which the filter apparatus of Example 8 was used.
  • As an anticoagulant solution a mixture of 250 ml of ACD-A solution and 250 ml of a physiological saline solution was continuously injected at a flow rate of 8 ml/min.
  • the filter material (B) of Example 8 was cut into a sheet (width: 150 mm, length: 1,500 mm) and the sheet was wound around a cylindrical mesh with a diameter of 31 mm made from polyethylene. A polyethylene mesh with a width of 150 mm and a length of 130 mm was further wound around the filter material (B) to obtain a hollow cylindrical filter.
  • a selective leukocyte removal filter apparatus was prepared in the same manner as in Example 8. In the selective leukocyte removal filter apparatus, the filling density of the filter material was 0.145 g/cm 3 , the filtration area of the first blood contact layer was 174 cm 2 , the volume standard specific surface area of the first blood contact layer was 0.33 m 2 /ml, and the thickness of the hollow cylindrical filter was 3.0 mm.
  • a selective leukocyte removal system for treating blood of a patient of systemic inflammatory response syndrome shown in Figure 2 was prepared. Extracorporeal circulation for one hour at a flow rate of 50 ml/min was conducted for the patient using the selective leukocyte removal system in which the above filter apparatus was used.
  • As an anticoagulant solution a mixture of 3,000 units of heparin and 500 ml of a physiological saline solution was continuously injected at a flow rate of 8 ml/min.
  • a mononuclear cell layer was separated from the blood using a Conray-Ficoll solution, the cells were stimulated with Concanavarin A (Con A) at a final concentration of 7 mg/ml per 1 x 10 6 mononuclear cells, then the cells were cultured for 24 hours to measure the TNF- ⁇ concentration of the supernatant.
  • Con A Concanavarin A
  • the concentration of 9,100 pg/ml before the treatment decreased to 4,800 pg/ml after the treatment, confirming suppression of the disease.
  • TNF- ⁇ activates leukocytes (neutrophil leucocytes) and induces a tissue damage, the decrease in the concentration is supposed to improve the inflammation symptom.
  • the present invention provides a polymer excelling in biocompatibility, exhibiting, in particular, only a low adsorption to platelets, and having a low elution property.
  • the filter material for selectively removing leukocytes, the selective leukocyte removal filter apparatus, and the selective leukocyte removal system using the biocompatible polymer can selectively remove leukocytes from various bloods, particularly from whole blood, while inhibiting adsorption of platelets, and are useful for platelet transfusion and extracorporeal circulation for leukocyte removal.

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EP03760160A 2002-06-17 2003-06-17 Biocompatible polymer and filter for selectively eliminating leucocytes using the same Expired - Lifetime EP1553113B1 (en)

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KR100892198B1 (ko) 2009-04-07
US7439013B2 (en) 2008-10-21
US20060073467A1 (en) 2006-04-06
JPWO2003106518A1 (ja) 2005-10-13
KR20050024336A (ko) 2005-03-10
WO2003106518A1 (ja) 2003-12-24
JP4587213B2 (ja) 2010-11-24
ATE414724T1 (de) 2008-12-15
CN100349934C (zh) 2007-11-21
AU2003244152A1 (en) 2003-12-31

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